1. Field of the Invention
The present invention relates to a transmission component, in particular a plate-link chain especially for continuously adjustable, belt-driven, conical pulley transmissions. More particularly, the plate-link chain includes individual chain links formed form plate-link sets that are connected by pairs of articulation members that are inserted into apertures of the plate links and are formed as rocker members having rocker faces supported against each other. Furthermore, the invention relates to a thrust-carrying link band, especially for continuously adjustable, belt-driven, conical pulley transmissions, with at least one closed belt strand and thrust links carried by the strand. In addition, the invention relates to a continuously adjustable, belt-driven, conical pulley transmission with a first shaft and a second shaft, whereby on each of the first and second shafts two conical disks are provided that have essentially conically-formed surfaces that face each other, whereby at least one conical disk per shaft is axially movable relative to the shaft.
2. Description of the Related Art
Such plate-link chains and transmissions are known from DE 38268009 and DE 195 44 644. Thrust link bands of the type mentioned above are known from DE 31 45 470.
In transmission components, such as plate-link chains, thrust link bands, and drive elements, because of substantial frictional forces in the frictionally-based force transfer between the endless torque-transmitting member and the conical disks in belt-driven, conical pulley transmissions, substantial pressing forces are necessary to support the drive torque transmitted by the transmission.
With increasing power concentrations at the friction points of the transmission, the losses that are therein dissipated also rise, and the thermal and mechanical load increases considerably, so that impermissibly high wear of contacting members can occur.
An object of the invention is to produce a transmission component, such as a plate-link chain, or in accordance with a further concept of the invention, a thrust link band, or in accordance with a further concept of the invention, a belt-driven, conical pulley transmission with conical disks, which relative to the state of the art particularly withstand a higher operating load or have a higher durability at the same load.
That object is advantageously attained in plate-link chains if at least the end faces of the rocker members that are in operative contact with the conical disks are provided with a nitrogen-enriched outer layer, such as a carbon-nitride layer.
In thrust link bands, that object is advantageously achieved if at least the end faces that come into operative contact with the thrust elements are provided with a nitrogen-enriched outer layer, such as a carbon-nitride layer.
In continuously adjustable, belt-driven, conical pulley transmissions, that object is advantageously achieved if at least the truncated conical surfaces of the conical disks that are in operative contact with an endless torque-transmitting means, such as a plate-link chain or a thrust link band, are provided with a nitrogen-enriched outer layer, such as a carbon-nitride layer.
It is thereby appropriate if the outer layer is characterized in such a way that a nitrogen content of at least 0.01%, advantageously at least in the range of 0.05% to 0.1%, is present in an outer layer of at least 50 xcexcm.
It is especially appropriate if besides a carbon-nitride process, a hardening process is likewise carried out. Thereby it is appropriate if the carburized depth in the region is greater than 0.3 mm, preferably greater than 0.5 mm.
In plate-link chains of the type mentioned, a stretching process of the extended plate-link chain is conducted, to increase the load-carrying capacity after assembly of the plate links and rocker members, in an open band in a straight strand while applying considerable pulling forces. In that way, contact areas of the plate links between the plate links and the rocker members of all plate links of a row are uniformly plastically deformed. In stretching the straight strand, an even plastic deforming of the plate links occurs in the contact areas, so that the plate links of a row of plate links are equally lengthened across the width of the plate links, or have the same length. That has the drawback that the chains do not manifest an optimal durability and performance capacity under load of the plate-link chain during operation of the continuously adjustable transmission.
An additional object of the invention is to produce a plate-link chain and a process for manufacturing a plate-link chain which, in relation to plate-link chains of the state of the art, especially withstand a higher operating toad or have a longer durability at the same load.
That is achieved in accordance with the invention with the above-mentioned plate-link chains in that the plate-link chain is stretched when in the closed condition.
The objective of the invention is also accomplished in that, with a plate-link chain of the type mentioned above, the plate links have a different plate-link inner width as a function of chain width. That result can be obtained in accordance with the invention by a stretching of the plate-link chain in the closed state, when it is in a loop.
The concept of plate-link inner width corresponds with the distance between the contours on which the two outer rocker members lie against the plate link. That is consequently a distance that is independent of whether the plate link has one central opening or two openings for receiving the rocker members. Further particulars are presented in the description of the figures.
It is, however, advantageous in another embodiment if the plate links are manufactured differently in the production process, such as by a stamping process or a cutting process, for example, or by means of a laser, or the like, and the individual plate links are stretched equally or differently and are assembled with one another or the assembled chain is stretched when in a loop.
It is also appropriate by a further embodiment if the plate links with the same plate-link inner width are produced by a stamping process and stretched differently and assembled with each other. In that embodiment the stretching can also be conducted on the individual plate links prior to assembly, or on the assembled chain when in a loop.
In accordance with a further concept of the invention, the objective of the invention can also be accomplished in connection with a plate-link chain of the type described above in that the plate links have a different degree of stretching as a function of the chain width.
That object can be advantageously accomplished in that the plate links with the same or different plate link inner widths are stretched with a different degree of stretching and can be assembled with each other. That object can also be achieved by stretching when in a loop.
In accordance with a further inventive concept, the objective of the invention can also be accomplished with a plate-link chain of the type described above in that the plate links have, as a function of chain width, a different angle between the contact areas and an axis viewed transversely to the longitudinal direction of the chain. In that way, a modulation or variation of that angle is achieved across the chain width, which allows a relatively good adaptation or position of the plate links to the partially curved rocker members during operation of the chain.
In accordance with a further inventive concept, the objective of the invention in a plate-link chain of the type described above can also be accomplished in that the plate links are acted upon in the stretching process with a stretching load at a variable angle in relation to the longitudinal direction of the plate links in that way, the plate links in their contact areas with the rocker members are stretched at different positions, and thereby strengthened such that they exhibit sufficient strength when loaded during operation of the chain, both in the straight strand between the pairs of conical disks as well as in the region of the pairs of conical disks.
It is especially advantageous if the plate links are individually stretched and subsequently assembled with one another. In another embodiment, it is appropriate that the plate links are stretched when in the assembled condition of a closed chain, such as especially in a loop arranged between two sets of conical disks of an apparatus.
The invention relates advantageously to plate-link chains in which at least one of the end faces of the rocker members per link facing the respective conical disks transmits the frictional forces between the conical disks and the plate-link chain. It can also be appropriate according to the application of the embodiment for the rocker members to be equally long or to be of different lengths.
The invention advantageously also relates, however, to plate-link chains in which the plate-link chain has, in addition to the rocker members, crosspins that transmit the frictional forces between the conical disks and the plate-link chain.
It is especially advantageous if the plate links adjacent to the edge of the plate-link chain are more highly lengthened than the plate links arranged in the middle of the plate-link chain, or if plate links adjacent to the edge of the plate-link chain have a greater inner width than the plate links arranged in the middle of the plate-link chain.
Furthermore, it is appropriate if areas of the plate links that contact the rocker members are plastically deformed by a stretching process, so that an angle is formed between the contact areas and a direction transverse to the longitudinal direction of the chain.
It is also appropriate when the plastically deformed contact areas of the plate links viewed across the width of the chain form a curved shape, or the shape of a polynomial of the nth degree.
It is especially advantageous if the plate-link chain is received in the gap between two pairs of conical disks and rotation and/or torque is applied during the stretching process.
It is also appropriate if the stress applied to the plate-link chain during the stretching process is caused by an axial load through contact pressure from the conical disk and/or through spreading apart of the axes of the pairs of conical disks. Accordingly, the invention also relates to an apparatus for stretching a plate-link chain. Thereby it is appropriate that the conical disks of the pairs of conical disks are movable relative to each other or are fixed.
During stretching of the plate-link chain it is appropriate if the torque that can be applied during the stretching process is substantially greater than the nominal torque during operation of a transmission equipped with a plate-link chain.
It is also appropriate for the torque applied during the stretching process to be in the region between zero and ten times, preferably three times to five times, the nominal torque during the operation of a transmission equipped with a plate-link chain.
It is also appropriate if the tension in the strand of chain during the stretching process is greater than the nominal tension during the operation of a transmission equipped with a plate-link chain.
The invention also relates to a process for manufacturing a plate-link chain and to a process for stretching a plate-link chain.